Effects of Selenomethionine on MsrB1, SELENOS, Caspase-3 and GADD45 genes expressions in mouse liver and brain samples

Abstract

Selenomethionine (SeMet) is an organic form of selenium, an essential trace element that plays an important role in reproduction, thyroid hormone metabolism, DNA synthesis, immune response regulation. This study aimed to evaluate the effects of SeMet concentration on genes responsible for redox regulation (MsrB1), regulation of protein folding, immune and inflammatory processes (SELENOS) as well as genes related to apoptosis and cell cycle control (Caspase-3 and GADD45) in mice liver and brain. The study was performed on 4‒6 week old BALB/c mice, which were divided into a control group that had free access to tap water, and groups that were given ad libitum tap water supplemented with different concentrations of selenomethionine (0.2 and 0.4 mg SeMet/kg of body weight) for the period of 8 weeks. After extracting mRNA from mouse liver and brain samples and performing complementary DNA synthesis, gene expression changes in the samples were determined by Real-time polymerase chain reaction. The obtained results showed that the expression of the Caspase-3 gene in both liver and brain samples was the highest among the control group, while the lowest expression was found among the mice that received 0.2 mg SeMet/kg. The expression of MsrB1 and SELENOS genes in the control groups of both samples is the lowest, while the expression of the mice exposed to 0.2 mg SeMet/kg is the highest. It was also found that with increasing SeMet concentration, GADD45 gene expression increased in liver samples and decreased in brain samples. According to the results, in mice treated with Selenomethionine, an increase in MsrB1 and SELENOS gene expression and a decrease in Caspase-3 gene expression in liver and brain samples, and an increase in GADD45 gene expression in liver samples lead to better cell survival associated with the crucial protection of these genes against inflammation, oxidative stress, DNA damage and apoptosis. However, as the concentration of SeMet increases, the decrease in GADD45 gene expression in brain samples may have a negative impact on cell functions, causing DNA damage.